Abstract: The non-destructive testing of the main steam pipeline of "Hualong One" was carried out in an open space using radiographic testing. Due to site limitations during the construction period, there were intersections between the office area, construction area, and testing operation area. During the implementation of radiographic testing, it was difficult to control the dosage and radiation scattering area of the operators. Through the application of radiation protection optimization methods and corresponding safety management control measures in the outdoor flaw detection process, from theoretical calculation, on-site testing to operation implementation, it effectively avoids personnel accidental exposure in outdoor open space flaw detection operations, reduces radiation safety risks, and also proposes that the setting of the main steam pipeline flaw detection area should be considered in the early stage of the project to eliminate the safety risks of radiation flaw detection in later open spaces.